<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .module {
            display: flex;
            justify-content: center;
            align-items: center;
            width: 300px;
            height: 200px;
            border: 1px solid #000;
        }
    </style>
</head>
<body>
    <div class="module">
        <div class="content">这是一个div</div>
    </div>
</body>
</html>